Re: [AUCTeX-devel] Automatic adding of label to optional argument

[Mosè Giordano]

Hi Arash,

2017-01-13 16:09 GMT+01:00 Arash Esbati <address@hidden>:
> --8<---------------cut here---------------start------------->8---
> (defun LaTeX-label (name &optional type no-insert)
>   "Insert a label for NAME at point.
> The optional TYPE argument can be either environment or section:
> in the former case this function looks up `LaTeX-label-alist' to
> choose which prefix to use for the label, in the latter case
> `LaTeX-section-label' will be looked up instead.  If TYPE is nil,
> you will be always prompted for a label, with an empty default
> prefix.
>
> If `LaTeX-label-function' is a valid function, LaTeX label will
> transfer the job to this function.
>
> If the optional NO-INSERT is non-nil, only the label is returned
> and no insertion happens.  Otherwise the inserted label is
> returned, nil if it is empty."
>   (let ((TeX-read-label-prefix
>          (cond
>           ((eq type 'environment)
>            (cdr (assoc name LaTeX-label-alist)))
>           ((eq type 'section)
>            (if (assoc name LaTeX-section-list)
>                (if (stringp LaTeX-section-label)
>                    LaTeX-section-label
>                  (and (listp LaTeX-section-label)
>                       (cdr (assoc name LaTeX-section-label))))
>              ""))
>           ((null type)
>            "")
>           (t
>            nil)))
>         label)
>     (when (symbolp TeX-read-label-prefix)
>       (setq TeX-read-label-prefix (symbol-value TeX-read-label-prefix)))
>     (when TeX-read-label-prefix
>       (if (and (boundp 'LaTeX-label-function)
>                LaTeX-label-function
>                (fboundp LaTeX-label-function))
>           (setq label (funcall LaTeX-label-function name))

The no-insert argument should be passed to the function and the
docstring of `LaTeX-label-function' updated accordingly.  This is a
breaking change, but I guess that for vast majority of users this
variable is either nil or points to `reftex-label'.

I suspect this function is starting to show the signs of aging.  This
`label' variable is not used after the function enters this branch, I
can't see why there is this is the `setq'.  `reftex-label' takes care
of adding the inserted label to the list of labels, so I think this
variable is not needed at all in the rest of function.

>         ;; Use completing-read as we do with `C-c C-m \label RET'
>         (setq label (TeX-read-label t "What label" t))
>         ;; No label or empty string entered?
>         (if (or (string= TeX-read-label-prefix label)
>                 (string= "" label))
>             (setq label nil)
>           ;; <change>
>           ;; If NO-INSERT, return only the label for further
>           ;; utilization, otherwise insert \label{label} in the buffer
>           (if no-insert
>               label
>             (insert TeX-esc "label" TeX-grop label TeX-grcl)))
>           ;; </change>
>         (if label
>             (progn
>               (LaTeX-add-labels label)
>               label)
>           nil)))))

Maybe I'm missing something also here, but I think that

--8<---------------cut here---------------start------------->8---
(if (or (string= TeX-read-label-prefix label)
    (string= "" label))
    (setq label nil)
  (insert TeX-esc "label" TeX-grop label TeX-grcl))
(if label
    (progn
      (LaTeX-add-labels label)
      label)
  nil)
--8<---------------cut here---------------end--------------->8---

can be safely replaced by

--8<---------------cut here---------------start------------->8---
(if (or (string= TeX-read-label-prefix label)
    (string= "" label))
    (setq label nil)
  (insert TeX-esc "label" TeX-grop label TeX-grcl)
  (LaTeX-add-labels label))
label
--8<---------------cut here---------------end--------------->8---

because `label' is the return value of `completing-read', which, up to
the best of my knowledge, always returns a string.

Bye,
Mosè